John Lotterio, 63, Pennsylvania. "[Obama's] killing people over energy by bottling over all the sources of energy, other than green energy. I saw on TV he said that if you want to invest in coal, go ahead, but you’re going to go bankrupt. What kind of attitude is that from that guy?"

This week, scientists announced that the extent of Arctic sea ice had reached its lowest level since measurements began. Here's everything you need to know about why vanishing Arctic ice matters—from sea level rise to permafrost to the opening of once-frozen areas for oil and gas exploration.

A new government report finds it's very unlikely that the record heat in the U.S. over the past 13 months was just a freak outburst of nature. So why do so many people still find it difficult to say that recent extreme weather events are being driven by man-made global warming?